Ball-and-socket joint

ABSTRACT

A ball-and-socket joint, preferably for chassis suspensions and/or steering mechanisms of motor vehicles, is presented, which has a ball pivot pin ( 1 ), which is accommodated rotatably and tiltably in a joint housing ( 8 ) with one of its free ends with a spherical joint area ( 3 ). The other free end of the ball pivot pin ( 1 ) is fixed to a body part. The ball-and-socket joint has a stop device for limiting the tilting movement of the ball pivot pin ( 1 ) in the joint housing ( 8 ), which comprises a stop element, which is arranged in the bottom area ( 11 ) of the joint housing ( 8 ) rotationally symmetrically to the longitudinal axis of the sphere and cooperates with the end-side joint area ( 6 ) of the ball pivot pin ( 1 ).  
     Corresponding to a first embodiment variant, the ball-and-socket joint has according to the present invention an arch projecting spherically over the bottom area ( 11 ) of the joint housing ( 8 ) as a stop element; a second solution variant provides for the stop element in the bottom area ( 11 ) of the joint housing ( 8 ) to have a hollow spherical shape, the radius of the hollow spherical shape being greater than the radius of the spherical shape of the joint area of the ball pivot pin ( 1 ).

SPECIFICATION

[0001] The present invention pertains to a ball-and-socket joint preferably for chassis suspensions and/or steering mechanisms of motor vehicles with the features described in the class-forming part of the independent claims 1 and 2.

[0002] Such a ball-and-socket joint is known especially from DE 42 44 886 C2. The angular mobility between the joint head and the joint housing of the ball-and-socket joint disclosed in that document is limited in that document by a stop device, which comprises a rotationally symmetrical, truncated cone-shaped stop on the housing, with which stop a counterstop formed by a corresponding recess in the joint head is associated at a spaced location.

[0003] Even though a stop element of such a design has proved, in principle, to be successful, it nevertheless has the drawback that in case of contact between the ball pivot pin and the truncated cone-shaped stop present on the housing, the bearing shell is partially subject to a very high load in the upper area facing the pivot area as a consequence of a developing lever action, which may lead to premature wear and a reduction of the overall service life of the ball-and-socket joint.

[0004] This is especially disadvantageous when the ball-and-socket joints with the possibility of the prior-art angular deflection limitation are loaded by the spring force and must bear the weight of the wheel carrier and brake disk in the fully deflected state of the vehicle.

[0005] The object of the present invention is therefore to improve a ball-and-socket joint of the type of this class such that premature wear of components that are important for the function, e.g., the bearing shell of the ball-and-socket joint, does not develop even under extreme load conditions, i.e., to provide a ball-and-socket joint in which the stop device permits a more uniform surface pressure between the ball pivot pin and the bearing shell for deflecting the ball pivot pin. At the same time, the manufacture of such a ball-and-socket joint shall become simpler and consequently less expensive.

[0006] Combined with the class-forming features, this object is accomplished by the technical teachings disclosed in the characterizing parts of the coordinate claims 1 and 2.

[0007] One basic idea of the present invention is to design the stop element as a convexly curved arch projecting preferably spherically over the bottom of the housing bottom.

[0008] As an alternative to this, the object can be accomplished by the stop element having a concave curvature, but preferably a hollow spherical shape at the housing bottom, the radius of the hollow spherical shape being greater than the radius of the spherical shape of the joint area of the ball pivot pin.

[0009] It is achieved through the technical solutions proposed that the spherical area of the ball pivot pin is raised during contact between this and the stop element designed according to the present invention, and the ball pivot pin is pressed uniformly to the upper end of the bearing shell facing the pivot area due to the raising. Another advantage of the solutions according to the present invention is that the ball pivot pin does not require any additional processing as a counterelement for the stop of the stop device at its joint ball-side end, at which a flattened area is present for manufacturing technical reasons. Thus, the same ball pivot pins can be used for ball-and-socket joints with and without stop device, which offers considerable advantages in terms of both the manufacturing technology and stocking.

[0010] The two alternative solutions according to the present invention will be explained in greater detail below on the basis of the drawings attached. In the drawings,

[0011]FIG. 1 shows a sectional view through a ball-and-socket joint with a stop device according to the first solution disclosed,

[0012]FIG. 2 shows a sectional view through the ball-and-socket joint from FIG. 1 in the deflected state,

[0013]FIG. 3 shows a sectional view through a ball-and-socket joint with a stop device according to the present invention according to variant 2, and

[0014]FIG. 4 shows a sectional view through the ball-and-socket joint according to the present invention from FIG. 3 with the ball pivot pin deflected.

[0015] The ball-and-socket joint shown in FIG. 1 comprises essentially a ball pivot pin 1, which has a pivot area 2 as well as a joint area 3. The pivot area 2 is provided with a conical mount 4, by means of which the ball pivot pin can be statically connected to a body part and can be fixed on the body part by the threaded part 5 at the free end of the pivot area 2. The joint area 3 has an essentially spherical shape and has a flattened area 6 caused by the manufacturing technology at its free end facing away from the pivot area 2. The joint area 3 is accommodated in a bearing shell 7, which is in turn fixed in a recess of a joint housing 8. The recess for the bearing shell 7 is designed as a blind hole with an opening 9, through which the bearing shell 7 can be introduced into the joint housing 8 together with the joint area 3 of the ball pivot pin 1. Once the said components have been accommodated in the joint housing 8, the joint housing 8 is closed by a closing ring 10, as a result of which the bearing shell 7 is fixed in the axial longitudinal direction of the ball-and-socket joint.

[0016] As can be clearly recognized from FIG. 1, the blind hole-like mounting hole in the joint housing 8 has a bottom area 11, which has a rotationally symmetrical arch 12 in the form of a ball surface projecting spherically in the direction of the flattened area 6 of the ball pivot pin 1. In case of a normal deflection of the ball pivot pin 1, an air gap 13 is present between the flattened area 6 and the surface of the arch 12. If the ball pivot pin 1 is greatly tilted within the bearing shell 7, as can be recognized from the view in FIG. 2, the air gap 13 decreases on one side until the flattened area 6 of the ball pivot pin 1 comes into contact with the arch 12 of the bottom area 11 in the blind hole of the joint housing 8 at the contact point 20. A further movement of the ball pivot pin 1 in the direction of arrow K leads to a displacement of the point 20 along the arch 12 and automatically to the raising of the ball pivot pin 1. The raising brought about by the arch 12 leads at the same time to a migration of the contact area 21 between the joint area 3 and the bearing shell 7 in the upper area of the closing ring 10. A punctiform load on the upper side of the bearing shell, which side is located in the area of the closing ring 10, is thus avoided in different tilted positions of the ball pivot pin 1, so that a special situation in terms of wear can be ruled out in this area despite the high load and the great tilting deflection of the ball pivot pin 1. The service life of the ball-and-socket joint according to the present invention shown in FIGS. 1 and 2 is thus prolonged. At the same time, it can be seen in FIGS. 1 and 2 that the stop device comprises, in principle, the arch 12 in the bottom area 11 of the joint housing, whereas the ball pivot pin 1 has the flattened area 6 at the end of the joint area 3 in the conventional manner and a special adaptation, as is necessary in the stop devices known from the state of the art, can thus be eliminated.

[0017] The ball-and-socket joint shown in FIGS. 3 and 4, in which the stop element is designed corresponding to the second solution variant, comprises essentially the same components as the ball-and-socket joint shown in FIGS. 1 and 2. Via the intermediary of a bearing shell 7, the joint area 3 of a ball pivot pin 1 is accommodated rotatably and tiltably in a joint housing 8 in this case as well. The bearing shell 7 and the joint area 3 are located here in a blind hole-like recess of the joint housing 8, which is shot [sic—typo for word meaning “closed”-Tr.Ed.] by a closing ring 10 after the insertion of the aforementioned two components. The ball pivot pin 1 has, analogously to the view in FIG. 1 or 2, a pivot area 2, with which the ball pivot pin 1 can be fixed on a body part, which is not shown here in greater detail for the sake of clarity. The stop device, by which the tilting movement of the ball pivot pin 1 is limited, comprises a special design of the bottom area 11 of the joint housing 8 in the embodiment variant according to FIGS. 3 and 4.

[0018] Corresponding to the second variant of the idea of the invention, the bottom area 11 is designed in the form of a hollow sphere, the radius of the hollow sphere having a greater diameter [sic-Tr.Ed.] than the radius of the sphere of the joint area 3 of the ball pivot pin 1. This is illustrated in FIGS. 3 and 4 by representing the spherical joint area 3 by dash-dot line beyond the flattened area 6, which is likewise present in this ball pivot pin 1, as a result of which it becomes clear that the radius of the spherical bottom area 11 has a markedly higher value.

[0019] The mode of action of this special design of the bottom area 11 becomes clear from FIG. 4, which shows the ball-and-socket joint with the ball pivot pin 1 tilted. The air gap 13, which is usually present between the flattened area 6 of the ball pivot pin 1 and the surface of the bottom area 11, decreases analogously to the view in FIG. 2 until the ball pivot pin 1 comes into contact with the bottom area 11 of the joint housing 8 in the area of the contact point 20.

[0020] A further deflection in the direction of arrow K leads to a displacement of the contact point 20 along the arch of the bottom area 11, so that a migration of the contact area 21 also begins at the same time in the upper area of the bearing shell adjacent to the closing ring 10. Thus, it is common to both embodiment variants that the deflection of the ball pivot pin 1 in the direction of arrow K after it comes into contact at the contact point 20 contributes to a raising, however slight, of the ball pivot pin 1 because of the special design of the bottom area, as a result of which a reduction of the surface pressure is brought about in the sensitive upper area of the bearing shell 7, contrary to the solutions known from the state of the art.

[0021] List of Reference Numbers

[0022] 1 Ball pivot pin

[0023] 2 Pin area

[0024] 3 Joint area

[0025] 4 Conical mount

[0026] 5 Threaded area

[0027] 6 Flattened area

[0028] 7 Bearing shell

[0029] 8 Joint housing

[0030] 9 Opening

[0031] 10 Closing ring

[0032] 11 Bottom area

[0033] 12 Arch

[0034] 13 Air gap

[0035] 20 Contact point

[0036] 21 Contact area 

1. Ball-and-socket joint, preferably for chassis suspensions and/or steering mechanisms of motor vehicles, with a said ball pivot pin (1), which is accommodated rotatably and tiltably in a said joint housing (8) with a said joint area (3) at one of its free ends and is fixed statically to a body part with a said pivot area (2) located at its other free end, and with a stop device for limiting the tilting movement of the said ball pivot pin (1) in the housing, having a stop element, which is arranged rotationally symmetrically to the longitudinal axis of the ball-and-socket joint in the said bottom area (11) of the joint housing and cooperates with the said end-side joint area (6) of the said ball pivot pin (1), characterized in that the stop element is designed as a said arch (12) projecting spherically over the said bottom area (11) of the joint housing.
 2. Ball-and-socket joint, preferably for chassis suspensions and/or steering mechanisms of motor vehicles, with a said ball pivot pin (1), which is accommodated rotatably and tiltably in a said joint housing (8) with a said joint area (3) at one of its free ends and is fixed statically to a body part with a said pivot area (2) located at its other free end, and with a stop device for limiting the tilting movement of the said ball pivot pin (1) in the housing, having a stop element, which is arranged rotationally symmetrically to the longitudinal axis of the ball-and-socket joint in the said bottom area (11) of the joint housing and cooperates with the said end-side joint area (6) of the said ball pivot pin (1), characterized in that the stop element in the said bottom area (11) of the said joint housing has a hollow spherical shape, the radius of the hollow spherical shape being greater than the radius of the spherical shape of the said joint area (3) of the said ball pivot pin (1). 